Dental chair



U' (No -Model.)Y

A. P. GoULD." DENTAL CHAIR.

" 4 Sheetsrsheet 3.

Patented Feb. 75.1893.

Afro/mfr (No Model.) A

4. .t e e h. s n e e .h s 4 wm A UH 0.0 GL .A Pm, .Uu *AD No. 491,097. Patented Pebl?, 1893.

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l l UNITED STATES APATENT OFFICE.

AARON P. GOULD, or CANTON, OHIO.

DENTAL CHAIR.

SPECIFICATION forming part of Letters Patent No. 491,097, dated February 7, 1893.

Application filed April 16, 1888. Serial No. 270.757. (No model.)

- To all whom it may concern.-

Be it known that I, AARON P. GOULD, a citizen of the United States, and a resident of Canton, county of Stark, State of Ohio, have invented a new and useful Improvement in Dental Chairs, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making part of this specification.

This invention relates to improvements in dental chairs and particularly to providing means for raising and lowering the body of the chair vertically.

With these ends in view my invention consistsin certain features of construction and combination of parts as'will be herein aft-er described and set forth in the claims.

Figure l, is an isometrical view of a dental chair, illustrating my improvements. Fig. 2, is a side elevation showing the parts in normal position, with the side of the frame removed. Fig. 3, is an isometrical view from the left and rear the parts being enlarged. Fig. 4c, isa vertical sectional view of the cylinder and piston. Fig. 5 is an enlarged perspective view of the lower portion of the chair, certain parts being broken away to show the operating partsI more clearly.

Similar letters of reference indicate corresponding parts in all of the gures of the drawings. v The base A (see Fig. l) is formed of two A-frames, coupled by a strut a and having on their inner faces vertical grooves a into which the slide a2 of frame B is adapted to fit for vertical movement, said frame having lugs a3 to which the locking frame a4 has a pivotal connection, and a downwardly projected lug a5, through which the spring supporting rod 0.6 passes (see Fig. 5) and against which the coil spring a7 rests, forming a bnier to arrest or prevent a jar when the body of the chair is quickly moved or swung about its pivotal connection with the frame B. To the downwardly projected lugs a8, on the cross piece x of frame B the upper end of the rack C is pivotally secured, the lower end corresponding with perforations in lugs z3 that project downwardly from the circular way D for a pivot or bolt whereby a pivotal connection X is formed between the frame B and thecircular way D. The circular body supporting frame E is pivotally secured to the circular supporting way D by a bolt .zt passed through the centrally located perforation b2 on the frameE resting on the circular way D. The parts referred to'in this paragraph are more fully shown and described in Fig. 2.

The foot lever H is pivotally secured to the strut, a, as shown in Fig. 3, the pawl E is pivotally secured thereto and held in engagement with the notches d4 on the lift rack C by the spring d5, one end of saidspring being secured to the strut a the other to a pin d6 projected from the upper end of pawl E. The pawl D has a pivotal support Z7 on the strut 0 one end of said pawl engaging the notches d8 on the rack C, the free end being provided with a foot plate (i9, and the other with a depending linger d10 which engages the pin d5 on the pawl E and moves the same forward, whereby the pawl E is disengaged from the notches d4 during the descent of the rack C. The engaging end of the pawl D is eccentric in form the outer end of the circu lar portion h being slightly drawn toward its pivotal center, that it may be drawn out lof the notch d8 gradually allowing the rack to move downward slowly until its movementis resisted by the fluid in the cylinder K hereinafter described. The pawl D is held in engagement with the rack C by the spring h', secured at its upper end to a linger, hx, pro'- jecting from the pawl, and at its lower end to an upright projecting from the bottom strut, h5, of the base, A.

ICO

To raise the frame B the foot is placed on the plate 71,3 on the lever H, and by a downward pressure the pawl E engaging the notches d4 the rack C pivotally secured to the frame B will raise the said frame and the chair body'thereon. By repeated movements of the lever H the chair may be raised to the desired height. `The reverse movement of the lever H is caused by the exertion of the coil spring h4. The pawl D holds the frame B and chair body in desired adjustment or elevation.

To lower the chair without jar a cylinder K, to contain a suitable fluid, is provided, the lower end resting on the bottom strut h5 of the base A, the upper end being provided with an annular screw thread h6 about which is fitted a cap 717 forming a packing space and means for compressing the packing as hs about the hollow piston rod L. The lower end of said piston rod L has a metal head 7c having a downwardly projected and centrally located pin 7c. Through said head are perforations 7a3, and valve 7a4 having a central perforation is placed on said pin 7c resting against the head 7c and over the perforations 7c8 and is held in said adjustment by the coil pring 705 resting on the removable screw head c 757 adapted to the annular bore of the cylinder K. Through the pin 7c is provided aperforation 708 into which is tted the pointed end 7 on the rod M. At the upper end of piston rod L is provided a metal head or support N having a portion adapted to the annular bore ofthe piston rod L, and 'an outwardly projeeted threaded portion m by which the pisvton rod may be removably secured to'the frame B by a nut as shown at n, Fig. 3.

Inthe head N there is provided a threaded perforation o into which the threaded end of the rod M is fitted, by which the rod may b e vertically adjusted and thereby adjust the pointed end 7 in perforation 70B, the said rod M being rotated by button head p. Thereis also provided in the head N a perforation q through which the fluid used may be passed into the piston and at the lower end of the piston perforationsr through which the fluid used may pass into the space in the cylinder about the piston. It will now be seen that when the hollow piston rod is plunged downward into the cylinder, the fluid can only pass through the opening, 758, into the piston rod, and as soon as the downward movement of the piston has ceased and the reverse movement effected,the liquid within the same will exert a pressure upon the valve, 7a4, press the same downward and quickly escape through the openings, 7a3, and 7c8, into the cylinder.

The operation is as follows, supposing the chair to be at its lowest position and the piston rod and cylinder above the piston head filled with any suitable fluid preferably oil or glycerine. To raise the chair, the operator presses his foot upon the lever H, the pawl E About the head 7c is placed a packing ring n engaging a notch d4 of the rack C, whereby the rack within the frame B and the body of the chair are raised a given distance and held in adjustment by the pawl D engaging a notch d8. This movement may be repeated until the body of the chair has reached a desired height in which adjustment it will be secured by the pawl D. As the piston has beenraised up in the cylinder the uid will have passed down through the perforations 7c3 and out over the valve into the cylinder To lower the chair the operator presses his foot on the pedal end of pawl D and thereby withdrawing the cam 7i from the notches d8 and dtwhich will allow the piston to settle gradually down on the fluid in the cylinder', the pointed end 7 of rod M being adjusted 1n the perforation lesto regulate the flow of ,the fluid back into the piston and thereby the descent ofthe chair s o long as the pawls D and E are held out of' engagement with the notches d8. The pawl D when released will engage the notch and hold the parts in'desired adjustment. As the pedal end of the pawl D is pressed downwardly the depending finger d10 disengages the Apawl E. It is not intended nor is it so provided lthat thepiston will hold the chair at any fixed point of adjustment. The pawl D lalone being provided for that purpose. A

Having thus fully described vthe nature and object of my invention, what I claim and desire to secure by Letters Patent, isz

l. The combination with the btise A, Of the frame B, of a rack C having (3o-operating pawls andlevers to raise and secure the chairbody in desired vertical adjustment, a Yfluidcontaining cylinder mounted o n the base A, a hollow piston secured to the body-,Supporting frame B, said piston adapted for vvertical movement in the fluid-containing cylinder, and having at its lower end an outwardlymoving valve 794,'an aperture 708 anda manually operated valve 7 carried by the piston by which the rapidity of descent of the chairbody may be previously determined by the flow of the fluid from the cylinder through the aperture 768 into the piston, substantially as set forth. g

2. The combination with the base A and frame B adapted to be reciprocated vertically therein of the rack. C, co-operating lifting and locking pawls and levers, of a fluid cylinder mounted on said base having a hollow piston of smaller diameter than the annular vbore of the cylinder, the upper end of said piston secured to the frame B, the lower end provided with a head 7c perforations 798, 7c3, in said head valves l and 7a4, for the respective perforations packing 767 surrounding said head and perforations r above the aforesaid perforations through which liuid may pass from the space about the piston to within the piston, substantially as set forth.

3. In a chair, the combination of the base A, frame B, rack C and co-operating pawls IOO IZO

and levers, to raise and secure the chair in desired adjustment, of the uid cylinder mounted on the base A, and a piston secured to the frame B, said piston provided with a downwardly opening out-let valve and a oentral opening 71:8 by which communication be? tween the piston and cylinder is at all times established, and a stem for regulating the flow of fluid through said opening los, whereby the downward movement of the chair maybe 1o regulated, substantially as set forth.k

In testimony whereof I khave hereunto set `my hand this 28th day of March, A. D. 1888.

AARON P. GoULD. 

